C + + Road set sail--Standard Template Library (queue)

Queue

FIFO queue: First in-line queue.

Priority queue: Outputs the priority size of the elements in the queue.

Defined:

FIFO Queue: queue< data class > variable name.

Priority queue:priority_queue< data type > variable name.

Eg:

FIFO queue: queue<int>que//defines a FIFO queue that is an integral type named Que.

Priority queue: priority_queue<int>que//defines a priority queue for an integral type named Que.

Overloaded operators are required when the type is a custom structure.

Eg:

struct ss//defines the structure of a SS
{
int x, y;
SS () {}//constructor
SS (int xx,int yy)//overloaded function
{
X=xx;
Y=yy;
}
BOOL operator< (const ss& B) const{//overloaded function operator.
Return y<b.y;
}
};

priority_queue<ss>que;//definition use;

Note: When invoking an action function, the type should also be a defined type, as the example can be manipulated with Que.push (SS) because it overloads the initial function.

Basic operation:

Que.empty ()//If the queue is not empty, returns false, otherwise true;

Que.szie ()//Returns the number of elements in the queue;

Que.pop ()//delete the first element of the team, but not return its value;

Que.front ()//Returns the value of the first element of the team, but does not delete the element (only for FIFO queues)

Que.back ()//Returns the value of the tail element of the queue, but does not delete the element (only for FIFO queues)

Q.top ()//Returns the value of the element with the highest priority, but does not delete the element (priority queue only)

Q.push ()//on queue; Press a new element at the end of the team; for Priority_queue, insert a new element at the current position based on the priority.

Code Explanation:

#include <cstdio>
#include <queue>
#include <iostream>

using namespace Std;

struct SS
{
int x, y;
SS () {}
SS (int xx,int yy)
{
X=xx;
Y=yy;
}
BOOL operator< (const ss& B) const{
Return y<b.y;
}
};
int main ()
{
priority_queue<ss>que1;
queue<int>que2;
Que2.push (1);
Que2.push (3);
Que2.push (2);
cout<< "Length of que2";
Cout<<que2.size () <<endl;
Que1.push (ss);
Que1.push (SS (2,3));
Que1.push (SS (3,4));
cout<< "Length of que1";
Cout<<que1.size ();
cout<< "The first element in the Que2";
Cout<<que2.front () <<endl;
cout<< "Delete first element in Que2" <<endl;
Que2.pop ();
cout<< "Length of que2";
Cout<<que2.size () <<endl;
cout<< "x and y values of the first element of the que1";
Cout<<que1.top () .x<< "" <<que1.top () .y<<endl;
}

C + + Road set sail--Standard Template Library (queue)